Known flip chip integrated packages (“FCIP”) include a chip mounted on a substrate within a mold compound. Specifically, with reference to FIGS. 1-2, a FCIP 10 is illustrated as including a chip 14 mounted on a substrate 12. The chip 14 includes conductive solder bumps 16 that contact a first surface 11 of the substrate 12. An underfill material 20 fills in the space around the under bumps 16 and between the substrate 12 and the chip 14. Solder balls 18 are positioned on a second surface 13 of the substrate 12 opposite from the first surface 11.
A mold compound 22 surrounds the chip 14 and adheres to the first surface 11 of the substrate 12 to provide physical and environmental protection to the chip 14. The composition of the mold compound 22 may be one of several compounds that are well known in the industry.
The mold compound 22 is normally applied to the package in a liquid or semi-liquid state of heightened temperature. As the mold compound 22 cools, gas expels from the mold compound and may become trapped within the package. Gas trapped in a semiconductor package causes numerous problems, chief among them being that the gas may eventually expand and cause the package to separate apart during either heat up and cool down during testing or during operation.
The underfill material 20 is utilized along with through-hole venting to assist in expelling any gas from the package to prevent gas from becoming trapped therein. Alternatively, sometimes a vacuum is used to pull gas from the mold compound 22. The use of underfill material 20 increases the tooling costs in the fabrication of flip chip integrated packages. Further, the use of vacuum increases the process costs in the fabrication of FCIPs.
There is therefore a need for a flip chip integrated package that eliminates the need for both underfill material and the use of a vacuum.